Bottle cap



FIG. 1 is a perspective view of a bottle cap, embodying my new design;

FIG. 2 is a rear elevational view thereof, the front elevational view thereof being a mirror image;

FIG. 3 is a top view thereof; and,

FIG. 4 is a side elevational view thereof, the opposite side elevational view thereof being the same.

The bottom of the bottle cap forms no part of the claimed design. 

The ornamental design for a bottle cap, as shown and described. 